The invention relates to a converter with a head part, which can be connected to an external data bus, and one or more connection modules, which can be connected to it by way of plug-in mounting in the form of rows, with the following features:                the head part has a plug-in connection with plug-in contacts associated with an internal data bus;        each connector module has a counter plug-in connection matching the plug-in connection of the head part;        counter plug-in contacts of the counter plug-in connection are connected to circuit connection contacts for the connection of a circuit support having an electronic circuit and to plug-in contacts for the connection of the counter plug-in contacts of a further connection module;        each connection module has at least one device connection for the connection of an actuator or a sensor, which communicates via the internal and external bus to a control device which can be connected to the external bus.        
A converter of this type is described by DE 200 15 758 U1. The head part, which is also described as a gateway, has a connection with which it can be connected to an external bus. Via this external bus, data are exchanged between the head part and a control device, for example a programmable controller. The external bus may be a field bus or the like. In the gateway, the data which are sent to the converter via the external data bus are converted and passed on via an internal data bus to the connection modules. Data of the internal data bus which are directed to the control device are passed by the gateway to the external bus. A multiplicity of connection modules can be connected to the head part in rows by way of a plug-in connection, it being possible in each case to connect to the head part a first connection module, to which a second connection module can be connected. By means of the plug-in contacts and counter plug-in contacts, the internal data bus is looped through the entire rows of connection modules disposed in rows. Each connection module has a device connection. Via this device connection, digital or analog data can be exchanged with devices, for example actuators or sensors. Each connection module additionally has an electronic circuit, which is associated with a circuit support and is exchangeably associated with the connection module. The circuit of the circuit support is adapted to the respective device to be connected to the connection module.
In the case of the converter of the known type, the plug-in contacts are open in such a way that the converter can be mounted only at protected locations.
It is known to set up the head and the individual connection modules in a row on a top-hat rail. In this case, the association takes place in the direction of extent of the top-hat rail, the plug-in contacts entering one another when the connection modules are pushed against one another. It is also known for the connection modules to be associated with one another in direction in relation to the direction of extent. In this case, contacts engage in one another in a blade-like manner. For this purpose, contact tabs protrude out of the wide side of the connection module, and slide in corresponding slots in the wide side of the neighboring connection module when the connection modules are brought into association with one another.
The invention is based on the object of providing a converter which can be easily produced but at the same time is robust.